1,647 research outputs found

    Molecular regulation of stem cell behavior during tissue repair and cancer formation

    Get PDF
    Oviedo will be presenting his work on identifying the mechanisms of adult stem cell fate determination based on their topographical location in the adult body. Understanding stem cell fate determination is crucial because tissue repair and neoplastic growth are greater in anterior than in posterior regions of adult animals. Despite its critical implications for stem cell biology, carcinogenesis and regenerative medicine, this physiological phenomenon has remained overlooked. Recent findings from his group provide intriguing evidence implying DNA repair mechanisms and cellular signaling through post-translational modifications regulate stem cell fate decision depending on their topographical location in the adult body. We have identified organ-specific cues and evolutionarily conserved cellular signaling pathways that can be therapeutically exploited to control stem cell behavior and cellular transformation in the complexity of the adult body

    Phase-dependent exciton transport and energy harvesting from thermal environments

    Get PDF
    Non-Markovian effects in the evolution of open quantum systems have recently attracted widespread interest, particularly in the context of assessing the efficiency of energy and charge transfer in nanoscale biomolecular networks and quantum technologies. With the aid of many-body simulation methods, we uncover and analyse an ultrafast environmental process that causes energy relaxation in the reduced system to depend explicitly on the phase relation of the initial state preparation. Remarkably, for particular phases and system parameters, the net energy flow is uphill, transiently violating the principle of detailed balance, and implying that energy is spontaneously taken up from the environment. A theoretical analysis reveals that non-secular contributions, significant only within the environmental correlation time, underlie this effect. This suggests that environmental energy harvesting will be observable across a wide range of coupled quantum systems.Comment: 5 + 4 pages, 3 + 2 figures. Comments welcom

    Enzymes as Feed Additive to Aid in Responses Against Eimeria Species in Coccidia-Vaccinated Broilers Fed Corn-Soybean Meal Diets with Different Protein Levels

    Get PDF
    This research aimed to evaluate the effects of adding a combination of exogenous enzymes to starter diets varying in protein content and fed to broilers vaccinated at day of hatch with live oocysts and then challenged with mixed Eimeria spp. Five hundred four 1-d-old male Cobb-500 chickens were distributed in 72 cages. The design consisted of 12 treatments. Three anticoccidial control programs [ionophore (IO), coccidian vaccine (COV), and coccidia-vaccine + enzymes (COV + EC)] were evaluated under 3 CP levels (19, 21, and 23%), and 3 unmedicated-uninfected (UU) negative controls were included for each one of the protein levels. All chickens except those in unmedicated-uninfected negative controls were infected at 17 d of age with a mixed oral inoculum of Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Live performance, lesion scores, oocyst counts, and samples for gut microflora profiles were evaluated 7 d postinfection. Ileal digestibility of amino acids (IDAA) was determined 8 d postinfection. Microbial communities (MC) were analyzed by G + C%, microbial numbers were counted by flow cytometry, and IgA concentrations were measured by ELISA. The lowest CP diets had poorer (P ≤ 0.001) BW gain and feed conversion ratio in the preinfection period. Coccidia-vaccinated broilers had lower performance than the ones fed ionophore diets during pre- and postchallenge periods. Intestinal lesion scores were affected (P ≤ 0.05) by anticoccidial control programs, but responses changed according to gut section. Feed additives or vaccination had no effect (P ≥ 0.05) on IDAA, and diets with 23% CP had the lowest (P ≤ 0.001) IDAA. Coccidial infection had no effect on MC numbers in the ileum but reduced MC numbers in ceca and suppressed ileal IgA production. The COV + EC treatment modulated MC during mixed coccidiosis infection but did not significantly improve chicken performance. Results indicated that feed enzymes may be used to modulate the gut microflora of cocci-vaccinated broiler chickens

    Effect of Electrolyte Balance in Low-Protein Diets on Broiler Performance and Tibial Dyschondroplasia Incidence

    Get PDF
    A proper dietary electrolyte balance (DEB) is essential to ensure an optimum acid-base equilibrium and broiler performance. In low-CP diets, this balance can be affected by reduction of soybean meal and inclusion of high levels of synthetic amino acids. Although, some studies have related low-protein diets supplemented with amino acids and DEB, these relations are not well explained, because some research demonstrates confusion about the deficiency and balance of nutrients. The objective of these experiments was to evaluate the DEB effects of diets with low levels of protein supplemented with amino acids on broiler performance and bone development. Results indicated that DEB and CP content influenced broiler chick performance in the starter and growing periods. There was no significant effect due to the interaction between DEB and CP content for tibial dyschondroplasia incidence (TD) or in bone breaking resistance during the growing period of either experiment. The incidence of TD was reduced with 253 mEq/kg DEB in the starter period

    Modification of ACSYNT aircraft computer program for preliminary design

    Get PDF
    This paper presents the development of a computer simulation of agility flight test techniques. Its purpose is to evaluate the agility of aircraft configurations early in the preliminary design phase. The simulation module is integrated into the NASA Ames aircraft synthesis design code. Trade studies using the agility module embedded within the design code to simulate the combat cycle time agility metric are illustrated using a Northrop F-20 aircraft model. Results show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can also compare the agility potential between different configurations and has the capability to optimize agility performance early in the design process

    Walk this way: Pedestrian accessibility and equity in Barranquilla and Soledad, Colombia

    Get PDF
    As a transport mode available to everyone and most abled-bodied urban residents, walking is, actually, the most equitable mode of transport. Walking brings several benefits to inhabitants among money savings and health improvement. Unfortunately, despite its benefits, walking is not a priority in the urban planning agenda of some cities, especially in the Global South. Walkability conditions in some areas of these cities are not particularly friendly for pedestrians, which discourage walking trips and promotes inequities across inhabitants. Evidence supporting inequalities in the provision of adequate conditions for the use of active transport in the Global South cities remain scarce. This paper aims to contribute to filling this gap by first proposing a framework to link pedestrian accessibility with walkability measures. Specifically, we use a macro-scale measure of pedestrian accessibility and a meso-scale measure of walkability to compare walking conditions on different zones in Barranquilla and Soledad, Colombia. After comparing both measures, we found that low-income zones have higher walkability indexes but present lower potential pedestrian accessibility. In contrast, the highest potential pedestrian accessibilities were located in high and medium-income zones, where people rely more on private transport modes. This imbalance regarding supply and demand conditions for walking trips suggest that unfortunately, zones with the highest potential of being walkable are the ones that face more barriers to walk. Then, adequate planning policies when implemented in the right locations could promote higher use of walking and have the potential to reduce current inequalities in pedestrian infrastructure provision

    Optimal Operation of a Distributed Generation Microgrid based on the Multi-Objective Genetic Algorithms

    Get PDF
    This document describes the application of multi-objective genetic algorithms as techniques and tools to optimize generation and distribution in small microgrids. In this way, genetic algorithms have been used for the allocation of distributed generation to reduce losses and improve the voltage profile. The IEEE14 network has been taken as a study and analysis model. This smart grid has 14 nodes and integrates several generation units, both conventional and renewable, transformers, and multiple loads. In this way, a multi-objective metaheuristic algorithm is proposed with the purpose of planning the power distribution grid based on a series of conditions such as the optimal generation configuration, the minimization of power losses in the lines, power transfer capacity, the reduction of CO2 emissions, and the optimization of the benefits obtained in renewable generation. The overall purpose is the development of an intelligent microgrid management system that is capable of determining the optimal configuration, by estimating demand, energy costs, and operating costs. © 2022, European Association for the Development of Renewable Energy, Environment and Power Quality (EA4EPQ). All rights reserved

    Mozambique: Urban Mobility, Accessibility & COVID-19

    Get PDF
    What policies have been put in place to limit the spread of COVID-19 in relation to mobility and accessibility
    • …
    corecore